This invention relates to by-pass valves for servicing a fluid line, and more particularly to a tamper-proof, by-pass valve for natural gas service.
Residential and commercial gas customers have a service stop valve for controlling gas flow to the customer. A supply conduit provides gas to the stop valve which when opened supplies gas to a meter. The gas passes to the customer from the meter through another conduit. It is sometimes necessary for the utility company to change and/or repair the meter and regulator. A by-pass valve and conduit are temporarily connected between the supply conduit and the customer connection to continue service to the customer during such a repair.
Prior art related to this type of service may be found in U.S. Pat. No. 6,283,153 issued Sep. 4, 2001, to Harlin J. Brisco et al. for xe2x80x9cFlow Valvexe2x80x9d; U.S. Pat. No. 3,187,570 issued Jun. 8, 1965, to Frank H. Mueller for xe2x80x9cBy-pass For Fluid Meterxe2x80x9d.
A problem with prior art by-pass valves is that unauthorized personnel can tap into a by-pass port intended to be used as a temporary gas connection. The present invention solves this problem by providing a tamper-proof valve having two security arrangements for protecting the by-pass port.
Typically the by-pass valve is a ball valve having a valve stem with a rectangular operator for opening and closing the ball valve element. The preferred valve body has a by-pass port for connecting a temporary conduit to supply gas to the consumer when the ball valve element is closed. A locking wing is carried on the valve stem. When the valve handle is turned to its fully open position, the locking wing is disposed over the by-pass port, preventing an unauthorized user from using a tool to remove a security plug in the by-pass port. When the ball valve is closed, the locking wing is turned to another position permitting a by-pass hose to be connected to the by-pass port, and permitting a padlock or industry specific device to lock the valve in its closed position.
Another feature of the invention is that the by-pass port is at one end of an internal by-pass passage in the body of the valve. When the by-pass passage is open and the ball valve is closed, gas flows from the supply conduit through the by-pass port and the by-pass passage to the customer""s supply conduit. A shutter valve is mounted in the valve body adjacent to the by-pass passage. A special tool is used to open the shutter valve, permitting gas flow through the by-pass passage. The shutter valve can be closed to block the by-pass passage, thus preventing unauthorized access to the gas flowing through the valve, by someone not having means for opening the shutter valve.
The security arrangements of the invention can be used on other types of valves, such as gate valves, butterfly valves and plug valves.
Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description.